The biosynthesis, synthesis (biomimetic) and metabolism of the following natural products (in the species indicated) are being investigated making use of both radioactive (14C, 3H) and stable (13C, 15N) isotopes. The location of the latter is determined by means of NMR. Nicotine, Nornicotine, Anatabine (in Nicotiana species), coniine and conhydrine (in Conium maculatum), scopolamine and atropine (in Datura species), tylophorine (in Tylophora species), cocaine (in Erythroxylon coca), 1-amino-cyclopropane-1-carboxylic acid (in pears), delta 1-tetrahydrocannabinol (in Cannabis sativa), sesbanine (in Sesbania drummondii), dendrocrepine (in Dendrobium crepidatum) psilocybin (in Psilocybes cubensis), mimosine (in Mimosa pudica).